From master repo:

Use xor to clear 32/16-bit registers instead of mov. ok ragge@, otto@

3 files changed, 86 insertions, 8 deletions

diff --git a/usr.bin/pcc/x86/local2.c b/usr.bin/pcc/x86/local2.c
index 117263171be..e5ab696747d 100644
--- a/usr.bin/pcc/x86/local2.c
+++ b/usr.bin/pcc/x86/local2.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: local2.c,v 1.1 2007/10/07 17:58:52 otto Exp $	*/
+/*	$OpenBSD: local2.c,v 1.2 2007/10/14 19:58:00 stefan Exp $	*/
 /*
  * Copyright (c) 2003 Anders Magnusson (ragge@ludd.luth.se).
  * All rights reserved.
@@ -26,7 +26,6 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-
 # include "pass2.h"
 # include <ctype.h>
 # include <string.h>
@@ -1047,6 +1046,18 @@ special(NODE *p, int shape)
 		    p->n_lval < 0 || p->n_lval > 0x7fffffff)
 			break;
 		return SRDIR;
+	case SMIXOR:
+		return tshape(p, SZERO);
+	case SMILWXOR:
+		if (o != ICON || p->n_name[0] ||
+		    p->n_lval == 0 || p->n_lval & 0xffffffff)
+			break;
+		return SRDIR;
+	case SMIHWXOR:
+		if (o != ICON || p->n_name[0] ||
+		     p->n_lval == 0 || (p->n_lval >> 32) != 0)
+			break;
+		return SRDIR;
 	}
 	return SRNOPE;
 }
diff --git a/usr.bin/pcc/x86/macdefs.h b/usr.bin/pcc/x86/macdefs.h
index c50b1e3e738..5fc828b02d3 100644
--- a/usr.bin/pcc/x86/macdefs.h
+++ b/usr.bin/pcc/x86/macdefs.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: macdefs.h,v 1.1 2007/10/07 17:58:52 otto Exp $	*/
+/*	$OpenBSD: macdefs.h,v 1.2 2007/10/14 19:58:00 stefan Exp $	*/
 /*
  * Copyright (c) 2003 Anders Magnusson (ragge@ludd.luth.se).
  * All rights reserved.
@@ -299,3 +299,10 @@ int COLORMAP(int c, int *r);
 #define	SHSTR		(MAXSPECIAL+1)	/* short struct */
 #define	SFUNCALL	(MAXSPECIAL+2)	/* struct assign after function call */
 #define	SPCON		(MAXSPECIAL+3)	/* positive nonnamed constant */
+
+/*
+ * Specials that indicate the applicability of machine idioms.
+ */
+#define SMIXOR		(MAXSPECIAL+4)
+#define SMILWXOR	(MAXSPECIAL+5)
+#define SMIHWXOR	(MAXSPECIAL+6)
diff --git a/usr.bin/pcc/x86/table.c b/usr.bin/pcc/x86/table.c
index 71d88e53499..fc2adc2df61 100644
--- a/usr.bin/pcc/x86/table.c
+++ b/usr.bin/pcc/x86/table.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: table.c,v 1.1 2007/10/07 17:58:52 otto Exp $	*/
+/*	$OpenBSD: table.c,v 1.2 2007/10/14 19:58:00 stefan Exp $	*/
 /*
  * Copyright (c) 2003 Anders Magnusson (ragge@ludd.luth.se).
  * All rights reserved.
@@ -794,17 +794,41 @@ struct optab table[] = {
 /*
  * The next rules takes care of assignments. "=".
  */
+{ ASSIGN,	FORCC|FOREFF|INLL,
+	SHLL,		TLL,
+	SMIXOR,		TANY,
+		0,	RDEST,
+		"	xorl AL,AL\n	xorl UL,UL\n", },
+
+{ ASSIGN,	FORCC|FOREFF|INLL,
+	SHLL,		TLL,
+	SMILWXOR,	TANY,
+		0,	RDEST,
+		"	xorl AL,AL\n	movl UR,UL\n", },
+
+{ ASSIGN,	FORCC|FOREFF|INLL,
+	SHLL,		TLL,
+	SMIHWXOR,	TANY,
+		0,	RDEST,
+		"	movl AR,AL\n	xorl UL,UL\n", },
+
+{ ASSIGN,	FOREFF|INLL,
+	SHLL,		TLL,
+	SCON,		TANY,
+		0,	RDEST,
+		"	movl AR,AL\n	movl UR,UL\n", },
+
 { ASSIGN,	FOREFF,
 	SHLL|SNAME|SOREG,	TLL,
 	SCON,		TANY,
 		0,	0,
 		"	movl AR,AL\n	movl UR,UL\n", },
 
-{ ASSIGN,	FOREFF|INLL,
-	SHLL,		TLL,
-	SCON,		TANY,
+{ ASSIGN,	FORCC|FOREFF|INAREG,
+	SAREG,	TWORD|TPOINT,
+	SMIXOR,		TANY,
 		0,	RDEST,
-		"	movl AR,AL\n	movl UR,UL\n", },
+		"	xorl AL,AL\n", },
 
 { ASSIGN,	FOREFF,
 	SAREG|SNAME|SOREG,	TWORD|TPOINT,
@@ -818,6 +842,12 @@ struct optab table[] = {
 		0,	RDEST,
 		"	movl AR,AL\n", },
 
+{ ASSIGN,	FORCC|FOREFF|INAREG,
+	SAREG,	TSHORT|TUSHORT,
+	SMIXOR,		TANY,
+		0,	RDEST,
+		"	xorw AL,AL\n", },
+
 { ASSIGN,	FOREFF,
 	SAREG|SNAME|SOREG,	TSHORT|TUSHORT,
 	SCON,		TANY,
@@ -1252,12 +1282,36 @@ struct optab table[] = {
 /*
  * Convert LTYPE to reg.
  */
+{ OPLTYPE,	FORCC|INLL,
+	SCREG,	TLL,
+	SMIXOR,	TANY,
+		NCREG,	RESC1,
+		"	xorl U1,U1\n	xorl A1,A1\n", },
+
+{ OPLTYPE,	FORCC|INLL,
+	SCREG,	TLL,
+	SMILWXOR,	TANY,
+		NCREG,	RESC1,
+		"	movl UL,U1\n	xorl A1,A1\n", },
+
+{ OPLTYPE,	FORCC|INLL,
+	SCREG,	TLL,
+	SMIHWXOR,	TANY,
+		NCREG,	RESC1,
+		"	xorl U1,U1\n	movl AL,A1\n", },
+
 { OPLTYPE,	INLL,
 	SANY,	TANY,
 	SCREG|SCON|SOREG|SNAME,	TLL,
 		NCREG,	RESC1,
 		"	movl UL,U1\n	movl AL,A1\n", },
 
+{ OPLTYPE,	FORCC|INAREG,
+	SAREG,	TWORD|TPOINT,
+	SMIXOR,	TANY,
+		NAREG|NASL,	RESC1,
+		"	xorl A1,A1\n", },
+
 { OPLTYPE,	INAREG,
 	SANY,	TANY,
 	SAREG|SCON|SOREG|SNAME,	TWORD|TPOINT,
@@ -1270,6 +1324,12 @@ struct optab table[] = {
 		NBREG,	RESC1,
 		"	movb AL,A1\n", },
 
+{ OPLTYPE,	FORCC|INAREG,
+	SAREG,	TSHORT|TUSHORT,
+	SMIXOR,	TANY,
+		NAREG,	RESC1,
+		"	xorw A1,A1\n", },
+
 { OPLTYPE,	INAREG,
 	SANY,	TANY,
 	SAREG|SOREG|SNAME|SCON,	TSHORT|TUSHORT,